1. Technical Field
The present invention is related to probing morphology of tissue, such as in vivo skin tissue in vivo.
2. Description of Related Art
The phenomena of changing polarization state of back scattered light from a turbid medium are well known. In 1988, Philip et al.[2] studied these phenomena in skin tissue and followed by Anderson et al.[3] in 1991. In 1998-2002 Jacques used a side illumination apparatuses.[4,5,6] In 2003, Anderson used his method for skin lesion boundary detection for Mohs micrographic surgery. [7] An enhanced view of vasculature and pigmented lesions was obtained. In 1999, Bueno et al.[8] showed an imaging of the eye retina by extracting the 16 parameters of Mueller matrix. The degree of polarization (DOP) was extracted from those images for the retinal plane. In 2004, Boulesteix et al.[9] used the method for stained hepatic biopsy, extracting the degree of polarization from Mueller matrices at the visible and near infrared spectral realms, and anomalous structure of the collagen was emphasized at different wavelengths. In the same year Ramella et al. [10] simplified the readout of two polarization (parallel and crossed polarizations compared with the light source polarization) from a tissue by using two cameras and calculated the normalized contrast between them simultaneously (S1 parameter of Stokes vector). Weber et al.[11] manipulated the cross and parallel polarizations separately so a tiny vein in the eye could be recognized. Liu et al.[12] measured the back-scattering Mueller matrix of a rat-skin sample almost in real-time using side illumination and the diattenuation, retardance and the depolarization parameters were deduced from the Mueller matrices. In 2005 Ramella et al.[13] described a better way to illuminate the tissue by skewed illumination for back scattered imaging and even a handy tool. [14] This allowed them to eliminate the glare with no need for oil or water as matching refractive index. Polarization contrast symbolized by Stokes parameters Pol=S1/S0 carry only few percentages of the light source. Thus in 2006 Zhao et al.[15] removed the noise by using adaptive wavelet transform method that can be easily applied to tissue imaging. Bruno et al.[16] constructed hemispherical spectro-polarimetric scattering instrument to manipulate series of Stokes parameters. In 2009 Zhao et al.[17] harnessed the principal component analysis (PCA) and image fusion[18,19] to the analysis of tissue characteristics and proposed a visual enhancement method to fuse the acquired spectral and polarimetric information by using false color mapping.
U.S. Pat. No. 7,289,211[1] discloses methods for calculating Stokes parameters on reflection from skin tissue.
Zhang et al. [20] performed research on an Asian male with a dark red skin and a Caucasian male with a light-pink skin. As a rule of thumb, these types of skin are the typical among all kinds of skin and surely suitable for spectral decision of preferable wavelengths.